The present invention relates to a core-forming explosive charge. Such charges are constituted in a well known manner by an explosive matter including on its face oriented toward the target a cavity, conical for example, with a vertex angle greater than 110.degree. and covered with a metal coating usually with a density greater than that of iron.
The detonation of the explosive matter generates very high pressure levels which result in the deformation of the coating and its transformation into a projectile the velocity of which is on the order of one to two kilometers per second.
These charges are called "flat charges" in contradistinction to the so-called "hollow charges" for which the cone vertex angle is greater than 90.degree., the latter charges forming an elongated jet-shaped projectile which is more fragile in regard to modern armor plates than the core formed by a flat charge.
Depending on the state of the art, flat charges are constituted by a coating made of a dense and usually metallic material, in contact on one side with the explosive matter and, on the other, with the air. Thus, upon detonation, the constituent material of the coating is subjected on one of its faces to a compression stress on the order of a few tens of Gigapascals and, on the other face, to a virtually null expansion-resistance exerted by the air. Consequently, the tensions accumulated in the coating can be released without any attenuation; this sudden expansion in contact with the air results usually in a scaling and a decoherence of the constituent material of the coating, particularly at its periphery. Consequently an important part of the coating mass will not be retained in the projected core, resulting in a poor energetic efficiency of the explosive charge. Therefore, it is impossible to use a "thick" coating (thickness greater than 10% and even 5% of the explosive charge length), as the mass losses in the matter transfer from the coating to the core are too high.